Comparing Pollutant Levels Between Different Diets

Comparing Pollutant Levels Between Different Diets.jpeg

The results of the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) study were published recently. This study of a California birth cohort investigated the relationship between exposure to flame retardant chemical pollutants in pregnancy and childhood, and subsequent neurobehavioral development. Why California? Because California children's exposures to these endocrine disruptors and neurotoxins are among the highest in the world.

What did they find? The researchers concluded that both prenatal and childhood exposures to these chemicals "were associated with poorer attention, fine motor coordination, and cognition" (particularly verbal comprehension) by the time the children reached school age. "This study, the largest to date, contributes to growing evidence suggesting that PBDEs [polybrominated diphenyl ethers, flame retardant chemicals] have adverse impacts on child neurobehavioral development." The effects may extend into adolescence, again affecting motor function as well as thyroid gland function. The effect on our thyroid glands may even extend into adulthood.

These chemicals get into moms, then into the amniotic fluid, and then into the breast milk. The more that's in the milk, the worse the infants' mental development may be. Breast milk is still best, but how did these women get exposed in the first place?

The question has been: Are we exposed mostly from diet or dust? Researchers in Boston collected breast milk samples from 46 first-time moms, vacuumed up samples of dust from their homes, and questioned them about their diets. The researchers found that both were likely to blame. Diet-wise, a number of animal products were implicated. This is consistent with what's been found worldwide. For example, in Europe, these flame retardant chemical pollutants are found mostly in meat, including fish, and other animal products. It's similar to what we see with dioxins--they are mostly found in fish and other fatty foods, with a plant-based diet offering the lowest exposure.

If that's the case, do vegetarians have lower levels of flame retardant chemical pollutants circulating in their bloodstreams? Yes. Vegetarians may have about 25% lower levels. Poultry appears to be the largest contributor of PBDEs. USDA researchers compared the levels in different meats, and the highest levels of these pollutants were found in chicken and turkey, with less in pork and even less in beef. California poultry had the highest, consistent with strict furniture flammability codes. But it's not like chickens are pecking at the sofa. Chickens and turkeys may be exposed indirectly through the application of sewer sludge to fields where feed crops are raised, contamination of water supplies, the use of flame-retarded materials in poultry housing, or the inadvertent incorporation of fire-retardant material into the birds' bedding or feed ingredients.

Fish have been shown to have the highest levels overall, but Americans don't eat a lot of fish so they don't contribute as much to the total body burden in the United States. Researchers have compared the level of PBDEs found in meat-eaters and vegetarians. The amount found in the bloodstream of vegetarians is noticeably lower, as you can see in my video Flame Retardant Pollutants and Child Development. Just to give you a sense of the contribution of chicken, higher than average poultry eaters have higher levels than omnivores as a whole, and lower than average poultry eaters have levels lower than omnivores.

What are the PBDE levels in vegans? We know the intake of many other classes of pollutants is almost exclusively from the ingestion of animal fats in the diet. What if we take them all out of the diet? It works for dioxins. Vegan dioxin levels appear markedly lower than the general population. What about for the flame retardant chemicals? Vegans have levels lower than vegetarians, with those who've been vegan around 20 years having even lower concentrations. This tendency for chemical levels to decline the longer one eats plant-based suggests that food of animal origin contributes substantially. But note that levels never get down to zero, so diet is not the only source.

The USDA researchers note that there are currently no regulatory limits on the amount of flame retardant chemical contamination in U.S. foods, "but reducing the levels of unnecessary, persistent, toxic compounds in our diet is certainly desirable."

I've previously talked about this class of chemicals in Food Sources of Flame Retardant Chemicals. The same foods seem to accumulate a variety of pollutants:

Many of these chemicals have hormone- or endocrine-disrupting effects. See, for example:

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: Mitchell Haindfield / Flickr. This image has been modified.

Original Link

Comparing Pollutant Levels Between Different Diets

Comparing Pollutant Levels Between Different Diets.jpeg

The results of the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) study were published recently. This study of a California birth cohort investigated the relationship between exposure to flame retardant chemical pollutants in pregnancy and childhood, and subsequent neurobehavioral development. Why California? Because California children's exposures to these endocrine disruptors and neurotoxins are among the highest in the world.

What did they find? The researchers concluded that both prenatal and childhood exposures to these chemicals "were associated with poorer attention, fine motor coordination, and cognition" (particularly verbal comprehension) by the time the children reached school age. "This study, the largest to date, contributes to growing evidence suggesting that PBDEs [polybrominated diphenyl ethers, flame retardant chemicals] have adverse impacts on child neurobehavioral development." The effects may extend into adolescence, again affecting motor function as well as thyroid gland function. The effect on our thyroid glands may even extend into adulthood.

These chemicals get into moms, then into the amniotic fluid, and then into the breast milk. The more that's in the milk, the worse the infants' mental development may be. Breast milk is still best, but how did these women get exposed in the first place?

The question has been: Are we exposed mostly from diet or dust? Researchers in Boston collected breast milk samples from 46 first-time moms, vacuumed up samples of dust from their homes, and questioned them about their diets. The researchers found that both were likely to blame. Diet-wise, a number of animal products were implicated. This is consistent with what's been found worldwide. For example, in Europe, these flame retardant chemical pollutants are found mostly in meat, including fish, and other animal products. It's similar to what we see with dioxins--they are mostly found in fish and other fatty foods, with a plant-based diet offering the lowest exposure.

If that's the case, do vegetarians have lower levels of flame retardant chemical pollutants circulating in their bloodstreams? Yes. Vegetarians may have about 25% lower levels. Poultry appears to be the largest contributor of PBDEs. USDA researchers compared the levels in different meats, and the highest levels of these pollutants were found in chicken and turkey, with less in pork and even less in beef. California poultry had the highest, consistent with strict furniture flammability codes. But it's not like chickens are pecking at the sofa. Chickens and turkeys may be exposed indirectly through the application of sewer sludge to fields where feed crops are raised, contamination of water supplies, the use of flame-retarded materials in poultry housing, or the inadvertent incorporation of fire-retardant material into the birds' bedding or feed ingredients.

Fish have been shown to have the highest levels overall, but Americans don't eat a lot of fish so they don't contribute as much to the total body burden in the United States. Researchers have compared the level of PBDEs found in meat-eaters and vegetarians. The amount found in the bloodstream of vegetarians is noticeably lower, as you can see in my video Flame Retardant Pollutants and Child Development. Just to give you a sense of the contribution of chicken, higher than average poultry eaters have higher levels than omnivores as a whole, and lower than average poultry eaters have levels lower than omnivores.

What are the PBDE levels in vegans? We know the intake of many other classes of pollutants is almost exclusively from the ingestion of animal fats in the diet. What if we take them all out of the diet? It works for dioxins. Vegan dioxin levels appear markedly lower than the general population. What about for the flame retardant chemicals? Vegans have levels lower than vegetarians, with those who've been vegan around 20 years having even lower concentrations. This tendency for chemical levels to decline the longer one eats plant-based suggests that food of animal origin contributes substantially. But note that levels never get down to zero, so diet is not the only source.

The USDA researchers note that there are currently no regulatory limits on the amount of flame retardant chemical contamination in U.S. foods, "but reducing the levels of unnecessary, persistent, toxic compounds in our diet is certainly desirable."

I've previously talked about this class of chemicals in Food Sources of Flame Retardant Chemicals. The same foods seem to accumulate a variety of pollutants:

Many of these chemicals have hormone- or endocrine-disrupting effects. See, for example:

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: Mitchell Haindfield / Flickr. This image has been modified.

Original Link

How Milk May Contribute to Childhood Obesity

How Milk May Contribute to Childhood Obesity.jpeg

We've known that breastfed infants may be protected against obesity later in life for more than 30 years, but why? It may be the formula. Giving infants formula based on cow's milk presents an unusual situation. Cow's milk is designed to put nearly two pounds a day onto a growing calf, 40 times the growth rate of human infants (see Formula for Childhood Obesity).

The perfect food for humans, finely tuned over millions of years, is human breast milk. Remarkably, among all mammalian species, the protein content of human milk is the lowest. The excessive protein content of cow's milk-based formula is thought to be what may be what sets the child up for obesity later in life.

And then, instead of being weaned, we continue to drink milk. The question thus arises as to whether consumption of a growth-promoting substance from another species throughout childhood fundamentally alters processes of human growth and maturation. A study out of Indiana University, for example, found evidence that greater milk intake is associated with an increased risk of premature puberty; girls drinking a lot of milk started to get their periods earlier. Thus, cross-species milk consumption and ingestion into childhood may trigger unintended consequences.

Only human milk allows appropriate metabolic programming and protects against diseases of civilization in later life, whereas consumption of cow's milk and dairy products during adolescence and adulthood is an evolutionarily novel behavior that may have long-term adverse effects on human health.

Teens exposed to dairy proteins such as casein, skim milk, or whey, experienced a significant increase in BMI and waist circumference compared to a control group. In contrast, not a single study funded by the dairy industry found a result unfavorable to milk.

The head of the Obesity Prevention Center at Boston Children's Hospital and the chair of Harvard's nutrition department wrote an editorial recently to the AMA's Pediatrics journal questioning the role of cow's milk in human nutrition. They stated the obvious: humans have no requirement for other animal's milk; in fact, dairy may play a role in certain cancers due to the high levels of reproductive hormones in the U.S. milk supply.


So what's The Best Baby Formula? Click on the link and find out!

More on dairy and infancy:

And in childhood: Childhood Constipation and Cow's Milk and Treating Infant Colic by Changing Mom's Diet

In adolescence: Saving Lives By Treating Acne With Diet

Before conception: Dairy Estrogen and Male Fertility

During pregnancy: Why Do Vegan Women Have 5x Fewer Twins?

And in adulthood:

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: Sergey Novikov © 123RF.com. This image has been modified.

Original Link

How Milk May Contribute to Childhood Obesity

How Milk May Contribute to Childhood Obesity.jpeg

We've known that breastfed infants may be protected against obesity later in life for more than 30 years, but why? It may be the formula. Giving infants formula based on cow's milk presents an unusual situation. Cow's milk is designed to put nearly two pounds a day onto a growing calf, 40 times the growth rate of human infants (see Formula for Childhood Obesity).

The perfect food for humans, finely tuned over millions of years, is human breast milk. Remarkably, among all mammalian species, the protein content of human milk is the lowest. The excessive protein content of cow's milk-based formula is thought to be what may be what sets the child up for obesity later in life.

And then, instead of being weaned, we continue to drink milk. The question thus arises as to whether consumption of a growth-promoting substance from another species throughout childhood fundamentally alters processes of human growth and maturation. A study out of Indiana University, for example, found evidence that greater milk intake is associated with an increased risk of premature puberty; girls drinking a lot of milk started to get their periods earlier. Thus, cross-species milk consumption and ingestion into childhood may trigger unintended consequences.

Only human milk allows appropriate metabolic programming and protects against diseases of civilization in later life, whereas consumption of cow's milk and dairy products during adolescence and adulthood is an evolutionarily novel behavior that may have long-term adverse effects on human health.

Teens exposed to dairy proteins such as casein, skim milk, or whey, experienced a significant increase in BMI and waist circumference compared to a control group. In contrast, not a single study funded by the dairy industry found a result unfavorable to milk.

The head of the Obesity Prevention Center at Boston Children's Hospital and the chair of Harvard's nutrition department wrote an editorial recently to the AMA's Pediatrics journal questioning the role of cow's milk in human nutrition. They stated the obvious: humans have no requirement for other animal's milk; in fact, dairy may play a role in certain cancers due to the high levels of reproductive hormones in the U.S. milk supply.


So what's The Best Baby Formula? Click on the link and find out!

More on dairy and infancy:

And in childhood: Childhood Constipation and Cow's Milk and Treating Infant Colic by Changing Mom's Diet

In adolescence: Saving Lives By Treating Acne With Diet

Before conception: Dairy Estrogen and Male Fertility

During pregnancy: Why Do Vegan Women Have 5x Fewer Twins?

And in adulthood:

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: Sergey Novikov © 123RF.com. This image has been modified.

Original Link

Evidence-Based Nutrition

NF-Jan12 Evidence-Based Medicine or Evidence-Biased?.jpg

Dr. Esselstyn's landmark study, demonstrating that even advanced triple vessel coronary artery disease could be reversed with a plant-based diet, has been criticized for being such a small study. But the reason we're used to seeing large studies is that they typically show such small effects. Drug manufacturers may need to study 7,000 people in order to show a barely statistically significant 15% drop in ischemic events in a subsample of patients. Esselstyn achieved a 100% drop in those who stuck to his diet, all the more compelling considering that those 18 participants experienced 49 coronary events (like heart attacks) in the eight years before they went on the diet. These patients were the sickest of the sick, most of whom having already failed surgical intervention. When the effects are so dramatic, how many people do you need?

Before 1885, a symptomatic rabies infection was a death sentence, until little Joseph Meister became the first to receive Pasteur's experimental rabies vaccine. The results of this and one other case were so dramatic compared with previous experience that the new treatment was accepted with a sample size of two. That is, the results were so compelling that no randomized controlled trial was necessary. Having been infected by a rabid dog, would you be willing to participate in a randomized controlled trial, when being in the control group had a certainty of a ''most awful death''? Sadly, such a question is not entirely rhetorical.

In the 1970's, a revolutionary treatment for babies with immature lungs called "extracorporeal membranous oxygenation" (ECMO), transformed immature lung mortality from 80% dead to 80% alive nearly overnight. The standard therapy caused damage to infants' lungs and was a major cause of morbidity and mortality in infants. ECMO is much gentler on babies' lungs, "providing life support while allowing the lungs to 'rest.'"

Despite their dramatic success, the researchers who developed ECMO felt forced to perform a randomized controlled trial. They didn't want to; they knew they'd be condemning babies to death. They felt compelled to perform such a trial because their claim that ECMO worked would, they judged, carry little weight amongst their medical colleagues unless supported by a randomized controlled trial. Therefore, at Harvard's Children's Hospital, 39 infants were randomized to either get ECMO or conventional medical therapy. The researchers decided ahead of time to stop the trial after the 4th death so as not to kill too many babies. And that's what they did. The study was halted after the fourth conventional medical therapy death, at which point nine out of nine ECMO babies had survived. Imagine being the parent to one of those four children.

Similarly, imagine being the child of a parent who died other conventional medical or surgical therapy for heart disease.

In her paper "How evidence-based medicine biases physicians against nutrition," Laurie Endicott Thomas reminds us that medical students in the United States are taught very little about nutrition (See Evidence-Based Medicine or Evidence-Biased?). Worse yet, according to Thomas, their training actually biases them against the studies that show the power of dietary approaches to managing disease by encouraging them to ignore any information that does not come from a double-blind, randomized controlled trial. Yet humans cannot be blinded to a dietary intervention--we tend to notice what we're eating--and, as a result, physicians are biased in favor of drug treatments and against dietary interventions for the management of chronic disease.

Evidence-based medicine is a good thing. However, Thomas points out that the medical profession may be focusing too much on one type of evidence to the exclusion of all others. Unfortunately, this approach can easily degenerate into "ignoring-most-of-the-truly-important-evidence" based medicine.

Heart disease is a perfect example. On healthy enough plant based diets, our number one cause of death may simply cease to exist. The Cornell-Oxford-China Study showed that even small amounts of animal-based food was associated with a small, but measurable increase in the risk of some chronic diseases. In other words, "the causal relationship between dietary patterns and coronary artery disease was already well established before Dean Ornish and Caldwell Esselstyn undertook their clinical studies." The value of their studies was not so much in providing evidence that such a dietary change would be effective, but in showing that "physicians can persuade their patients to make such changes," and in "providing interesting data on the speed and magnitude of the change in severe atherosclerotic lesions as a result of dietary therapy."

Therefore, any complaints that these studies were small or unblinded are simply irrelevant. Because the evidence of the role of diet in causing atherosclerosis is already so overwhelming, "assigning a patient to a control group eating the standard American diet could be considered a violation of research ethics."

Evidence of the value of plant-based diets for managing chronic disease has been available in the medical literature for decades. Walter Kempner at Duke University, John McDougall, the Physician's Committee for Responsible Medicine, Nathan Pritikin, and Denis Burkitt all warned us that the standard Western diet is the standard cause of death and disability in the Western world. Yet physicians, especially in the US, are still busily manning the ambulances at the bottom of the cliff instead of building fences at the top.

If you're not familiar with Dr. Esselstyn's work, I touch on it in:

Sadly, medical students learn little about these powerful tools:

If you haven't heard of Pritikin, I introduce him here: Engineering a Cure

An intro to Dr. Ornish: Convergence of Evidence

Dr. Burkitt: Dr. Burkitt's F-Word Diet

The Cornell-Oxford-China Study: China Study on Sudden Cardiac Death

Dr. Walter Kempner: Kempner Rice Diet: Whipping Us Into Shape

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: clement127 / Flickr

Original Link

The Dietary Link Between Acne and Cancer

NF-Jan7 Saving Lives By Treating Acne With Diet.jpg

Acne is an epidemic skin disease of industrialized countries, reaching prevalence rates of over 85 percent of teenagers. In nearly half of American men and women, acne even continues after adolescence and into the third decade of life.

Acne is considered a disease of Western civilization, as in places like Okinawa, Japan, acne is rare or even nonexistent. So acne is not some "physiological" phenomenon of puberty, but may represent "a visible risk indicator pointing to aberrant nutrient signaling promoting chronic epidemic diseases of civilization," according to a group of German researchers (See Saving Lives By Treating Acne With Diet). What they mean is that the dairy, junk foods, meat, and egg proteins in Western diets all conspire to raise the activity of the enzyme TOR, contributing to acne and obesity. Therefore, using diet to suppress TOR may not only improve acne, but may also prevent the march to more serious chronic TOR-driven diseases of civilization. The excessive TOR stimulation induced by the standard American diet may initially manifest as premature puberty and acne, but then may later contribute to obesity, diabetes, cancer and Alzheimer's.

A lot of this research is relatively new. Until recently, for example, only a weak association had been accepted for the role of milk and dairy products in acne formation. However, there is now substantial evidence supporting the effects of milk and dairy products as enhancers of acne aggravation. Milk is not just food, but appears to represent a most sophisticated hormone signaling system activating TOR, which is of critical concern given that TOR is recognized as the fundamental driving force for a number of serious chronic diseases.

If milk is naturally supposed to stimulate TOR, why the problem? Because we're drinking milk from the wrong species. Cow's milk is designed for calves. Baby cows grow nearly 40 times faster than human infants. Cow's milk has three times more leucine, the primary activator of TOR, than breast milk, so cow's milk may over-stimulate TOR when consumed by humans. It's like giving donkey milk to rats--it doesn't make sense. Furthermore, milk is for babies, so the continued consumption of any kind of milk during adolescence and adulthood is something that never really happened naturally and may have long-term adverse effects on human health.

In this regard, it's kind of frightening to realize that more than 85 percent of teens in Western countries exhibit acne; it implies that the "majority of our population is living with over-activated TOR signaling, a major disease-causing factor, which may pave the way for the development of other more serious diseases." A history of acne has been associated with breast cancer risk in women, for example, and prostate cancer in men.

So early dietary counseling of teenage acne patients is thus a great opportunity for dermatologists, who will not only help to improve acne but may reduce the long-term adverse effects of Western diet on more serious TOR-driven diseases. So just like urologists use erectile dysfunction as an opportunity to save lives by putting people on heart-healthy diets, dermatologists can use acne as a way to save lives by putting people on a cancer prevention diet.

How do you turn acne on and off via dietary manipulation of TOR? A "comprehensive dietary strategy to treat acne can only be achieved by higher consumption of vegetables and fruit and reduction of animal-derived food" given preliminary evidence for the effectiveness of natural plant-derived TOR inhibitors in the treatment of acne.

TOR is considered the engine-of-aging enzyme detailed in Why Do We Age? and Caloric Restriction vs. Animal Protein Restriction, as well as my video Prevent Cancer From Going on TOR.

I've touched on this topic before in Acne and Cancer and covered acne and dairy in:

Urologists saving the lives of men is detailed in Survival of the Firmest: Erectile Dysfunction and Death and 50 Shades of Greens.

What else are Okinawans doing right? See The Okinawa Diet: Living to 100.

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: coniferconfier / Flickr

Original Link

How to Suppress the Aging Enzyme TOR

NF-Jan5 Prevent Cancer From Going on TOR.jpg

Over the last decade, more than 5,000 papers have been published about TOR, an engine-of-aging enzyme inhibited by the drug rapamycin. (What is TOR? Check out my videos Why Do We Age? and Caloric Restriction vs. Animal Protein Restriction.) Rapamycin has been used experimentally to extend lifespan, but is already in use clinically to prevent the rejection of kidney transplants. Patients who received rapamycin due to renal transplantation had a peculiar "side effect," a decrease in cancer incidence. In a set of 15 patients who had biopsy proven Kaposi's sarcoma (a cancer that often affects the skin), all cutaneous sarcoma lesions disappeared in all patients within three months after starting rapamycin therapy.

TOR functions as a master regulator of cellular growth and proliferation. For example, TOR is upregulated in nearly 100% of advanced human prostate cancers (See Prevent Cancer From Going on TOR). So, reductions in cancerous lesions after rapamycin therapy make sense. TOR may also be why dairy consumption has been found to be a major dietary risk factor for prostate cancer. We used to think it was just the hormones in milk, but maybe prostate cancer initiation and progression is also promoted by cow's milk stimulation of TOR.

Our understanding of mammalian milk has changed from a simple food to a "species-specific endocrine signaling system," which activates TOR, promoting cell growth and proliferation and suppressing our body's internal housecleaning mechanisms. Normally, milk-mediated TOR stimulation is restricted only to infancy where we really need that constant signal to our cells to grow and divide. So from an evolutionary perspective, "the persistent 'abuse' of the growth-promoting signaling system of cow's milk by drinking milk over our entire life span may maintain the most important hallmark of cancer biology, sustained proliferative signaling."

TOR appears to play a role in breast cancer, too. Higher TOR expression has been noted in breast cancer tumors, associated with more aggressive disease, and lower survival rate among breast cancer patients. Altered TOR expression could explain why women hospitalized for anorexia may end up with only half the risk of breast cancer. Severe caloric restriction in humans may confer protection from invasive breast cancer by suppressing TOR activation.

We don't have to starve ourselves to suppress TOR; just reducing animal protein intake can attenuate overall TOR activity. Moreover, diets emphasizing plants, especially cruciferous vegetables, have both decreased TOR activation from animal proteins and provide natural plant-derived inhibitors of TOR found in broccoli, green tea, soy, turmeric, and grapes, along with other fruits and vegetables such as onions, strawberries, blueberries, mangoes and the skin of cucumbers.

The downregulation of TOR may be one reason why plant-based in general are associated with lower risk for many cancers. "Are we finally on the threshold of being able to fundamentally alter human aging and age-related disease?" asks researchers in the journal Nature. Only time will tell, but if the pace and direction of recent progress are any indication, the next 5,000 studies on TOR should prove very interesting indeed.

More on dairy and prostate cancer in Prostate Cancer and Organic Milk vs. Almond Milk.

This story continues in my video: Saving Lives By Treating Acne With Diet.

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Grempz / Flickr

Original Link

Is it Better to Bake, Boil, or Steam Sweet Potatoes?

NF-Nov19 best method for cooking sweet potatoes.jpg

I previously talked about the cancer fighting properties of sweet potatoes (See Anti-Cancer Potential of Sweet Potato Proteins) and what would happen if you centered your diet around them (The Okinawa Diet: Living to 100). It seems that the only potential downside to eating too many sweet potatoes is that you could get yellow palms (or nose as you can see in the video, The Best Way to Cook Sweet Potatoes), a harmless condition called "carotenemia." Caused by elevated levels of beta carotene in the blood, it was first noticed a century ago when carrots were introduce into infant diets. It's treated mostly by just reassuring parents that it's harmless, but if we don't want our child's nose to be yellow, we can decrease their beta carotene intake and in a few months it will be gone.

When picking out varieties at the supermarket, the intensity of the yellow or orange flesh color of the sweet potato is directly correlated to its nutritional content, so the more intense the better. Though if you really want intensity, sweet potato varieties don't just range from white to yellow and orange, but from pink to deep purple. The natural pigments that cause these colors may have special anticancer effects.

What is the best way to cook sweet potatoes? Boiling may actually retain most of the antioxidant power of sweet potatoes, compared to roasting and steaming. If we compare baking to boiling microscopically, boiling helps thin out the cell walls and gelatinize the starch, which may enhance the bioavailability of nutrients. At the same time, the glycemic index of boiled sweet potatoes was found to be about half that of baking or roasting, so boiled sweet potatoes give us less of a blood sugar spike.

Make sure to keep the skin on, though. The peel of a sweet potato has nearly ten times the antioxidant power as the flesh (an antioxidant capacity comparable to that of blueberries). However, the peel's nutrition really takes a hit when baked, which wipes out over two thirds of the antioxidants, whereas microwaving or boiling are comparatively much gentler. The same is true for the rest of the sweet potato. Baking can also cause an 80% drop in vitamin A levels, twice as much as boiling. Therefore, from a nutritional standpoint, boiling rather than baking should be recommended for cooking sweet potato.

Boiling may theoretically be best, but sweet potatoes are so incredibly healthy that the actual best way to prepare them is whichever way will get you to eat the most of them! The exception is deep frying, which can lead to the formation of acrylamide, a potential human carcinogen.

What about cooking methods for other vegetables? See my video Best Cooking Method.

Want more information about acrylamide, the potential crispy carb carcinogen? See my video Cancer Risk from French Fries. And for why deep frying in general might not be good, Deep Frying Toxins and Carcinogens in the Smell of Frying Bacon.

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Avital Pinnick / Flickr

Original Link

Dr. Greger’s 2015 Live Year-in-Review Presentation

Food as Medicine

View my new live presentation here: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet

Every year I scour the world's scholarly literature on clinical nutrition, pulling together what I find to be the most interesting, practical, and groundbreaking science on how to best feed ourselves and our families. I start with the thousands of papers published annually on nutrition (27,000 this year--a new record!) and, thanks to a crack team of volunteers (and now staff!), I'm able to whittle those down (to a mere 8,000 this year). They are then downloaded, categorized, read, analyzed, and churned into the few hundred short videos. This allows me to post new videos and articles every day, year-round, to NutritionFacts.org. This certainly makes the site unique. There's no other science-based source for free daily updates on the latest discoveries in nutrition. The problem is that the amount of information can be overwhelming.

Currently I have more than a thousand videos covering 1,931 nutrition topics. Where do you even begin? Many have expressed their appreciation for the breadth of material, but asked that I try to distill it into a coherent summary of how best to use diet to prevent and treat chronic disease. I took this feedback to heart and in 2012 developed Uprooting the Leading Causes of Death, which explored the role diet may play in preventing, arresting, and even reversing our top 15 killers. Not only did it rise to become one of the Top 10 Most Popular Videos of 2012, it remains my single most viewed video to date, watched over a million times (NutritionFacts.org is now up to more than 1.5 million hits a month!).

In 2013 I developed the sequel, More Than an Apple a Day, in which I explored the role diet could play in treating some of our most common conditions. I presented it around the country and it ended up #1 on our Top 10 Most Popular Videos of 2013. Then in 2014 I premiered the sequel-sequel, From Table to Able, in which I explored the role diet could play in treating some of our most disabling diseases, landing #1 on our Top 10 Most Popular Videos of 2014.

Every year I wonder how I'm going to top the year before. Knowing how popular these live presentations can be and hearing all the stories from folks about what a powerful impact they can have on people's lives, I put my all into this new 2015 one. I spent more time putting together this presentation than any other in my life. It took me an entire month, and when you see it I think you'll appreciate why.

This year, I'm honored to bring you Food as Medicine, in which I go through our most dreaded diseases--but that's not even the best part! I'm really proud of what I put together for the ending. I spend the last 20 minutes or so (starting at 56:22) going through a thought experiment that I'm hoping everyone will find compelling. I think it may be my best presentation ever. You be the judge.

You can watch it at no cost online, but it is also available on DVD through my website or on Amazon. If you want to share copies with others, I have a five for $40 special (enter coupon code 5FOR40FAM). All proceeds from the sales of all my books, DVDs, downloads, and presentations go to the 501c3 nonprofit charity that keeps NutritionFacts.org free for all, for all time. If you want to support this initiative to educate millions about eradicating dietary diseases, please consider making a donation.

After you've watched the new presentation, make sure you're subscribed to get my video updates daily, weekly, or monthly to stay on top of all the latest.

-Michael Greger

Original Link

How to Reduce Exposure to Alkylphenols Through Your Diet

NF-Apr28 Dietary Sources of Alkylphenol Endocrine Disruptors.jpg

Alkylphenols are industrial chemicals that are found in hair products, spermicides, cleaning products and detergents. They are considered endocrine disruptors. For more information on alkylphenols, check out my video Alkylphenol Endocrine Disruptors and Allergies.

Concern about alkylphenols first surfaced decades ago when a group at Tufts observed an excessive proliferation of human breast cancer cells in certain types of plastic containers, something that would normally only be seen if the cells were exposed to some type of estrogen. They identified an alkylphenol leaching from the plastic as the culprit, having "estrogen-like properties when tested in the human breast tumor cells." Excessive proliferation of human breast cancer cells is never good, so countries in Europe started banning and restricting the use of these chemicals. However, the U.S. EPA has been slow to respond.

A half million tons of alkylphenols continue to spew out into the environment every year, so much so that now that they come down in the rain and then accumulate up the food chain.

One study, highlighted in my video, Dietary Sources of Alkylphenol Endocrine Disruptors, examined the Japanese food supply to find out which foods had these potentially allergy-exacerbating endocrine disruptors. The researchers found that chicken and fish had the highest levels. Water animals and birds concentrate these compounds to levels several thousands of times greater than those in the environment because these are fat-soluble chemicals. "Therefore, they can easily contaminate foods of animal origin, which are thought to represent the most important source of human exposure to many organic pollutants," not just the alkylphenols. Another research group also found that fish was the worst.

Which kind of fish? Anchovies, mackerel, salmon and cod seem to have the highest levels. In fact, salmon was the only food found contaminated with nonylphenol diethoxylate, which is even more potent than regular nonylphenol. The levels of contamination in fish were at the concentrations that start to make breast cancer cells go crazy in vitro.

These findings are consistent with the fact that seafood consumption has been associated with severe asthma, current and severe rhinoconjunctivitis, (seasonal pollen allergies), and current and severe eczema (an allergic-type disease of the skin) in adolescent populations around the globe.

If these synthetic xenoestrogens are playing a role, what about natural phytoestrogens, such as those found in soy foods? It turns out that in patients with asthma, consumption of a diet with moderate to high amounts of soy phytoestrogens is associated with better lung function and better asthma control. If anything then, it's these chemical pollutants, which come down in the rain, contaminate the soil, the plants, and then concentrate up the food chain in the fat of animals. We're now the animals at the top of the food chain, like the polar bear or bald eagle, building up higher levels of these synthetic xenoestrogens.

Thankfully, there aren't many cannibals around anymore. However, there is one group that continues to feed off human tissues--babies (See The Wrong Way to Detox). Alkylphenols have been found to concentrate in human breast milk, particularly in women who eat fish. The highest levels of these endocrine-disrupting pollutants were recorded in milk samples from mothers who said they ate fish at least twice a week, consistent with the fact that seafood consumption represents an important source of alkylphenol intake. Even these "slightly elevated levels of endocrine disruptors in the milk of mothers with a seafood-rich diet may be associated with adverse effects on neurological development, fetal and postnatal growth, and memory functions on breastfed infants, because these contaminants may interfere with the endocrine [hormonal] system."

Since these toxins concentrate in fat, the highest concentrations may be found in straight animal fat, such as chicken fat, lard, tallow, or fish oil. Consumption of fish oil capsules and processed fish products has been associated with alkylphenol concentration in mothers' milk, again due to bioaccumulation up the food chain. And then we recycle the leftover remains of farm animals into farm animal feed, so the levels can get higher and higher in animal products.

As one commentator noted, while these pollutants do contaminate human milk, they also contaminate cow's milk--humans and cows live in the same polluted world. In fact, infant formula was found to be over five times more contaminated, so breast is still best, absolutely. But these kinds of studies are important in order to provide good suggestions for food choices to nursing mothers to prevent excess exposure to these pollutants in their infants.

We can kind of cut out the middlefish and move lower down the food chain in hopes of decreasing our exposure to industrial toxins.

Endocrine disruptors have also been linked to conditions such as male infertility (Male Fertility and Diet and Xenoestrogens and Sperm Counts) and early onset of puberty (Protein, Puberty, and Pollutants and Xenoestrogens and Early Puberty).

What other industrial pollutants build up in the aquatic fish chain? See, for example:

Farmed Fish vs. Wild Caught. Which is worse?

How Long to Detox from Fish Before Pregnancy? If it's too late, How Fast Can Children Detoxify from PCBs?

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: Andrea Pokrzywinski / Flickr

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